Preflushing unit for carrying out a preflushing operation in a breathing gas circuit of a closed-circuit respirator

Abstract

A preflushing unit ( 10 ) preflushes a breathing gas circuit ( 210 ) of a closed-circuit respirator ( 200 ). A basic body ( 20 ) has an inlet port ( 22 ), feeding breathing gas from a breathing gas supply ( 220 ), an outlet port ( 24 ) discharging breathing gas into the breathing circuit, and a flow section ( 32 ) fluid connecting a valve chamber ( 30 ). A valve body ( 40 ) with a sealing surface ( 42 ) is arranged in the valve chamber ( 30 ). An elastomer body ( 50 ) with a counter-sealing surface ( 52 ) in the valve chamber, fluid tight separates the flow section from a control section ( 34 ). The counter-sealing surface acts with a sealing force against the valve body for sealing the flow section. A control port ( 26 ) of the basic body provides a controlled feed of breathing gas from the breathing gas supply into the control section for pressure equalization between the flow section and the control section.

The invention claimed is: 
     
       1. A preflushing unit for carrying out a preflushing operation in a breathing gas circuit of a closed-circuit respirator, the preflushing unit comprising:
 a body with an inlet port for a feed of breathing gas from a breathing gas supply and with an outlet port for a discharge of breathing gas into the breathing gas circuit, wherein the inlet port and the outlet port are fluid connected to a valve chamber in the body via a flow section; 
 a valve body with a sealing surface arranged in the valve chamber; and 
 an elastomer body with a counter-sealing surface in the valve chamber, wherein the counter-sealing surface further fluid tight separates the flow section from a control section and is formed of an elastic material, wherein the counter-sealing surface is configured to act with a sealing force against the sealing surface of the valve body for closing a fluid pathway that extends between the inlet port and the outlet port via the flow section, wherein the body further has a control port for a controlled feed of breathing gas from the breathing gas supply into the control section at a lower rate of pressure rise than from the breathing gas supply into the flow section via the inlet port for pressure equalization between the flow section valve chamber and the control section; 
 a gas carrying device having a mounting port configured to receive the breathing gas from the breathing gas supply, a preflushing outlet configured to transfer the breathing gas from the mounting port to the inlet port of the body, a refill port configured to transfer the breathing gas from the mounting port to the breathing gas circuit of the closed-circuit respirator, and a control outlet configured to transfer breathing gas from the mounting port to the control port of the body, the outlet port of the body being in fluid connection with the refill port. 
 
     
     
       2. The preflushing unit in accordance with  claim 1 , wherein the inlet port and the outlet port have an identical or essentially identical flow cross section. 
     
     
       3. The preflushing unit in accordance with  claim 1 , wherein the elastomer body has a rotationally symmetrical counter-sealing surface configuration. 
     
     
       4. The preflushing unit in accordance with  claim 1 , wherein the valve body has a rotationally symmetrical sealing surface configuration. 
     
     
       5. The preflushing unit in accordance with  claim 1 , wherein the valve body is arranged centrally or essentially centrally in the flow section. 
     
     
       6. The preflushing unit in accordance with  claim 1 , wherein the sealing surface is arranged at a widening sealing section of the valve body. 
     
     
       7. The preflushing unit in accordance with  claim 1 , wherein the body has an auxiliary port in fluid-communicating connection with the control section for a fluid-communicating connection to an auxiliary control volume. 
     
     
       8. The preflushing unit in accordance with  claim 1 , further comprising a dispensing unit arranged in the control port with a dispensing opening for passage of breathing gas from the breathing gas supply into the control section, the dispensing unit being a separate component, the body being configured to accept different dispensing units with dispensing openings of correspondingly different sizes. 
     
     
       9. The preflushing unit in accordance with  claim 1 , further comprising fastening devices arranged at the inlet port, at the outlet port and/or at the control port for a fluid-tight fastening of breathing gas tubes. 
     
     
       10. A closed-circuit respirator comprising:
 a breathing gas circuit; 
 a preflushing unit comprising:
 a body with an inlet port for a feed of breathing gas from a breathing gas supply and with an outlet port for a discharge of breathing gas into the breathing gas circuit, wherein the inlet port and the outlet port are fluid connected to a valve chamber in the body via a flow section; 
 a valve body with a sealing surface arranged in the valve chamber; and 
 an elastomer body with a counter-sealing surface in the valve chamber, wherein the counter-sealing surface further fluid tight separates the flow section from a control section and is formed of an elastic material, wherein the counter-sealing surface is configured to act with a sealing force against the sealing surface of the valve body for closing the a fluid pathway that extends between the inlet port and the outlet port via the flow section, wherein the body further has a control port for a controlled feed of breathing gas from the breathing gas supply into the control section for pressure equalization between the flow section and the control section; 
 
 a gas-carrying device comprising a mounting port for the breathing gas supply, a refill port configured to discharge breathing gas into the breathing gas circuit, wherein the mounting port is fluid connected to the inlet port via a preflushing outlet and to the control port of the preflushing unit via a control outlet, the outlet port of the preflushing unit being further fluid connected to the refill port. 
 
     
     
       11. The closed-circuit respirator in accordance with  claim 10 , wherein the mounting port has a pressure reducer for the reduction of the high pressure in the breathing gas supply to a medium pressure. 
     
     
       12. A process for a preflushing operation in a closed-circuit respirator using a gas-carrying device and a preflushing unit,
 the gas-carrying device comprising:
 a mounting port for a breathing gas supply, a refill port configured to discharge breathing gas into a breathing gas circuit of the closed-circuit respirator, wherein the mounting port is fluid connected to an inlet port of the preflushing unit via a preflushing outlet and to a control port of the preflushing unit via a control outlet, an outlet port of the preflushing unit being further fluid connected to the refill port, 
 
 the preflushing unit comprising:
 a body with the inlet port for a feed of breathing gas from the breathing gas supply and with the outlet port for a discharge of breathing gas into the breathing gas circuit, wherein the inlet port and the outlet port are fluid connected to a valve chamber in the body via a flow section; a valve body with a sealing surface arranged in the valve chamber; and an elastomer body with a counter-sealing surface in the valve chamber, wherein the counter-sealing surface further fluid tight separates the flow section from a control section and is formed of an elastic material, wherein the counter-sealing surface is configured to act with a sealing force against the sealing surface of the valve body for closing the a fluid pathway that extends between the inlet port and the outlet port via the flow section, wherein the body further has the control port for a controlled feed of breathing gas from the breathing gas supply into the control section for pressure equalization between the flow section and the control section, 
 
 the process comprising the steps of: 
 connecting the breathing gas supply to the mounting port; 
 providing an outflow of breathing gas via the preflushing outlet through the inlet port of the preflushing unit, through the flow section into the breathing gas circuit via the outlet port; and 
 providing an inflow of breathing gas via the control outlet and via the control port of the preflushing unit into the control section until pressure equalization is obtained with the flow section.